A push-push switch is generally known which comprises an operation shaft movable inwardly of a housing and actuating a movable contact. A heart-shaped cam is provided within the housing for locking selectively the operation shaft at a certain position, and is designed so that in response to initial movement of the operation shaft within the housing, this shaft is locked by the heart-shaped cam in a position where the movable contact engages a first fixed contact. In response to further inward movement of the operation shaft, it is released from the locked state and the movable contact engages another fixed contact. In the foregoing structure, the heart-shaped cam pivots reciprocatingly in response to the bias of a recovery spring and the movement of the operation shaft, whereby the foregoing locking function is attained.
In the foregoing example of a conventional structure, because the heart-shaped cam is designed so that it is biased constantly by a coil spring and pivotable, the lock mechanism portion of the switch needs a large space. Further, because the coil spring must be positioned within the housing under a compressed state when assembling the switch, the assembling process is troublesome and the productivity is poor.